Gene boost lets plant tolerate low boron in soil

Researchers have genetically modified a plant to make it tolerate low levels of boron, a nutrient often lacking from soils, especially in southeast China and Pakistan.

The researchers say it is likely that a similar approach could be used in crop species to provide a cheap alternative to using boron fertiliser which can cause pollution.

The scientists, whose findings were published on 22 May in The Plant Journal, modified Arabidopsisthaliana,a relative of mustard that is often used in research on plant genetics.

Toru Fujiwara of the University of Tokyo, Japan and colleagues increased the activity of the plant's BOR1 gene, which controls the uptake of boron. The genetically modified (GM) Arabidopsis plants produced more seeds under low boron conditions than non-GM plants and were twice as heavy.

Previously, researchers developed tobacco plants able to tolerate low boron levels but this affected the plant's ability to process sugars.The approach used by Fujiwara's team is advantageous as most plants have genes very similar to BOR1 and boosting the gene's action is likely to affect only boron uptake.

Abdul Rashid, chief soil scientist at Pakistan's National Agricultural Research Center, told SciDev.Net that after zinc deficiency, a lack of boron is the most widespread micronutrient problem for crops. It affects at least 132 plant species in 80 countries.

It increases plants' susceptibility to diseases and affects flower development and seed growth, causing a decline in quality in crops such as rice and wheat.

Research suggests that rising greenhouse gas emissions will make the problem worse as plants are likely to require more nutrients, particularly boron, as levels of carbon dioxide in the atmosphere increase.

Rashid welcomes the new finding but cautions that it will take time before other GM crops that can tolerate boron-deficient soils are available.

"Even after such plants become commercially available, we need to find out whether their genetic potential can be realised without applying boron fertiliser in soil-deficient situations", he told SciDev.Net.